1. Field of the Invention
This invention relates to a turbocharging pressure controlling apparatus for controlling the pressure of air to be supplied to an internal combustion engine from a turbocharger rotated by exhaust gas from the internal combustion engine and, more particularly, to improvements in minimizing the mounting space therefor.
2. Description of the Prior Art
FIG. 1 is a sectional view showing an example of a conventional turbocharging pressure controlling apparatus. In FIG. 1, numeral 1 designates a bracket mounted to an internal combustion engine (not shown), a case 2 being mounted to the bracket 1. In the case 2 there is provided a rubber-made diaphragm 3 held between a positive pressure side holder 4 and an atomspheric side holder 5 so that the interior of the case 2 is divided into two chambers, namely, an atmospheric chamber 6 and a positive pressure chamber 7. A spring holder 9 is disposed on the interior surface of the atmospheric chamber 6, and is opposite to the atmospheric side holder 4, and between the spring holder 9 and the atmospheric side holder 4 there is provided a spring 8 which normally urges the diaphragm 3 toward the positive pressure chamber 7. A nipple 10 is mounted to the case 2, its front end facing one side wall of the positive pressure chamber 7. One side wall of the atmospheric chamber 6 is provided with a hole 11 through which the chamber 6 communicates with the open air. A rod 12 is mounted movably back and fourth, extending through the spring holder 9 and the case 2, its base end being fixed to the atmospheric-side holder 5 and positive pressure-side holder 4.
A control valve 13 is mounted to the front end of the rod 12 through a link 14. The valve 13 has a function to adjust the degree of opening of a flow dividing hole 15 bored in an exhaust pipe 16 for guiding exhaust gas to a turbocharger (not shown) which operates to increase the pressure of air to be supplied to the internal combustion engine. Through this adjustment the pressure of air to be supplied from the turbocharger to the internal combustion engine is regulated.
The conventional turbocharger pressure controlling apparatus is constructed as above described, so that the rod 12 is caused to extend outwardly against the biasing force of the spring 8 by air of several atmospheres being introduced through the nipple 10 into the positive pressure chamber 7, the flow dividing hole being then opened by the control valve 13. As a consequence, the amount of exhaust gas to be supplied to the turbine is reduced and the rotation speed of the turbine is lowered, the amount of air to be supplied to the internal combustion engine being thus decreased.
With the conventional turbocharging pressure controlling appartus of such arrangement, when the pressure of air to be supplied to the internal combustion engine is lowered, the rod 12 is caused to operate in the direction of arrow A, and therefore the apparatus involves the difficulty that, when mounting the apparatus to an internal combustion engine, its mounting position is sometimes limited.